A Novel Regenerative Electrohydraulic Brake System: Development and Hardware-in-Loop Tests

The development of a novel electrohydraulic brake system named REHB is presented in this paper. Neither high-pressure accumulator nor linear valves are adopted to reduce the system cost, the difficulty of manufacturing, assembling, and the risk of leakage. Stroke simulators are implemented to elevate the quality of pedal feel. The braking force blending control strategy is well designed to coordinate regenerative and friction brake force, which has ensured maximized regenerative brake force. In the aspect of underlying control, current amplitude modulation control is adopted to improve the accuracy of hydraulic pressure modulation and eliminate vibration noise. High fidelity models of vehicle and brake system are built based on MATLAB-AMESim co-simulation platform. Three demand levels of one-step-brake scenarios are simulated. Simulation results show the reasonability of proposed hydraulic structure and designed control strategy. A regenerative brake test bench is set up based on a prototype of the developed system. Three identical one-step-brake experiments are conducted on the test bench. According to the bench test results, the blending of regenerative and friction brake force tracks driver brake demand adequately well. Regenerative efficiencies are calculated as 46.32%, 43.93%, and 31.88%, respectively, in three bench tests. Compared with the previous generation, no obvious valve buzzing noise is observed, and jerks are whittled significantly. REHB has provided a brake-by-wire solution of safety, high energy recuperation efficiency with low cost, and uncompromising performance.